Skip to content
An Elixir library for generating struct constructors that handle external data with ease.
Branch: master
Clone or download
Latest commit d6c1ea7 Feb 1, 2017
Type Name Latest commit message Commit time
Failed to load latest commit information.
.gitignore first release Jan 19, 2016


wercker status Coverage Status Version

ExConstructor is an Elixir library that makes it easy to instantiate structs from external data, such as that emitted by a JSON parser.

Add use ExConstructor after a defstruct statement to inject a constructor function into the module.

The generated constructor, called new by default, handles map-vs-keyword-list, string-vs-atom-keys, and camelCase-vs-under_score input data issues automatically, DRYing up your code and letting you move on to the interesting parts of your program.


defmodule TestStruct do
  defstruct field_one: nil,
            field_two: nil,
            field_three: nil,
            field_four: nil
  use ExConstructor
end{"field_one" => "a", "fieldTwo" => "b", :field_three => "c", :FieldFour => "d"})
# => %TestStruct{field_one: "a", field_two: "b", field_three: "c", field_four: "d"}

Full Documentation

Full ExConstructor documentation is available on


Many thanks to those who've contributed to ExConstructor:

How to Contribute

My favorite contributions are PRs with code that matches project style, and that come with full test coverage and documentation. I have a hard time saying no to them.

Feature requests are also welcome, but the timeline may be much longer.

Bug reports are great -- please include as much information as possible (Erlang/Elixir/Mix version, dependencies and their versions, minimal test case, etc.) and I will be much quicker in resolving the issue.

Authorship and License

ExConstructor is copyright 2016-2017 Appcues, Inc.

ExConstructor is released under the MIT License.

You can’t perform that action at this time.